my brothers just got a new car as his girlfriend upgraded due to hers having a fault on it.

its idleing funny, bouncing up and down from about 1800 to 2200.
its had a new throttle body on it and that didnt fix it.
there is an 8 pin plug on the side of the throttle body that i think is a choke of some description.

when that is unplugged it idles ok.
i took the air filter and housing out the way and with the plug connected you can see the butterfly valve open and close slightly with the idle. if i hold it down it helps but its being driven by a motor so i cant hold it fully closed.

also if you start the car with this plug out and plug it in once running it dosent cause it to idel funny.

today we changed the colant temp sensor and that didnt change anything.
we changed the plugs and they come out very black so it does seam something is causing it to run rich and idle strange.

anyone got any other ideas on what could cause the choke to kick in and cause these problems?